Methanol is generally made from a mostly methane hydrocarbon feed by first catalytically oxidizing the feed at high temperature to produce a synthesis gas. This oxidation reaction is known in the art as hydrocarbon reforming. Reforming is usually conducted using steam as an oxidant, however, steam reforming is frequently supplemented by secondary reforming using oxygen or an oxygen-containing gas. Methanol is then catalytically synthesized from the direct combination of the hydrogen and carbon oxides in the synthesis gas. Because of a low molecular carbon to hydrogen ratio for saturated hydrocarbon feeds and a minimum required steam rate, hydrogen is generally present in large stoichiometric excess in the synthesis gas. However, a large hydrogen excess is undesirable for methanol synthesis and much effort has been expended to balance the stoichiometric composition of the synthesis gas. U.S. Pat. No. 4,888,130 to Banquy, for example, discloses a process for producing a synthesis gas suitable for methanol production or other synthesis requiring a low H.sub.2 /CO ratio. The feedstock is divided into two fractions and the first fraction undergoes primary steam reforming. The gas effluent is combined with the second feedstock fraction and undergoes secondary reforming with an oxygen-containing gas.
Alternatively, the significant hydrogen-rich stream from methanol production is available for further use such as, for example, ammonia production. U.S. Pat. No. 3,598,527 to Quartulli et al., for example, discloses a process for the production of methanol and ammonia. This process involves operating sequentially and in series a high pressure hydrocarbon reforming zone, a low pressure methanol synthesis zone, a water shift conversion zone, a carbon dioxide removal zone, and an ammonia synthesis zone. The reforming zone includes air reforming following steam reforming to provide nitrogen sufficient to satisfy the requirement for ammonia production. Carbon dioxide removal includes a regenerative CO.sub.2 absorption system and methanation to eliminate residual carbon oxides.
U.S. Pat. No. 4,315,900 to Nozawa et al. discloses an integrated process for the production of methanol and ammonia wherein secondary steam and air reforming to produce an ammonia synthesis gas follows the methanol synthesis. A methanol synthesis gas is produced by primary steam reforming of a hydrocarbon feed. Shift converters are used to reduce CO content of the ammonia synthesis gas and CO.sub.2 removal is effected by absorption and methanation prior to ammonia synthesis.
U.S. Pat. No. 4,367,206 to Pinto discloses a method for producing methanol and ammonia by generating a nitrogen containing synthesis gas, reacting the carbon oxides and hydrogen incompletely to methanol and passing the unreacted gas to ammonia synthesis. The process is characterized by catalytic methanol synthesis in a first steam-free stage and then in a second stage in the presence of sufficient steam to convert substantially all the unreacted CO to CO.sub.2. Methanol can be taken from the second synthesis stage as a product or vaporized and recycled as a source of steam for this stage. Recycling concentrates the methanol inlet concentration to the catalyst and suppresses the net formation of methanol for increasing subsequent ammonia production.
U.S. Pat. No. 4,810,417 to Diemer et al. discloses a process for the simultaneous production of methanol synthesis gas and ammonia synthesis gas from crude coal gasification products.